This invention relates to lasers, and more particularly, to high efficiency storage lasers.
There are many requirements for high efficiency lasers which emit in the infrared and visible portion of the spectrum. Very few of the presently available lasers meet this requirement. Conventional solid state lasers generally employ broad band black body pump sources such as xenon flash lamps. These lamps are highly efficient in the conversion of electrical to optical energy (typically 30%). However, to efficiently couple to such sources it is necessary that the laser medium have absorption bands which match the broad band emission of the pump source. There are very few solid state materials in this category with Neodyium (Nd) being the most often used. Nd, however emits only in the infrared and at best has an efficiency on the order of 2%.
Most laser materials and particularly those using rare earths (the bulk of solid state lasers) tend to have isolated narrow absorption bands. In order to improve efficiency for such lasers it has been proposed to resonantly pump rare earth lasers such as Er:LiYF.sub.4, Er-Ho:LiYF.sub.4 and Er-Ho:LiYF.sub.4 with the output from a doubled Nd:YAG laser. This is disclosed in U.S. patent application Ser. No. 953,243, filed Oct. 20, 1978 and assigned to assignee of the present application. Improving efficiency in this manner only works if the pump laser itself is efficient and there are only a very few which suffice.
Accordingly, it is an object of the present invention to provide a high efficiency laser.
It is another object of this invention to provide a high efficiency laser which emits in the visible.